The man, in his late 20s and who appeared to be impaired, began attacking several passengers on the bus, Camden said.

As the bus stopped at 63rd Street, the man then attacked the bus driver, said Camden.

As the man was attacking the driver, another passenger got off the bus and flagged down a passing police car with a single officer inside, Camden said.

A statement from Police News Affairs said the officer was an evidence technician.

As the man noticed that a police officer was approaching the bus, he took off some of his clothing and was flailing his arms at the police officer in a threatening manner, despite being ordered to stop, Camden said.

The subject disregarded police orders and aggressively advanced towards the officer, and as a result of this action the officer discharged his weapon, according to the police statement.

After the man continued to attack, the officer shot the man, Camden said. The man began going toward the officer again, who shot the man again, Camden said.

After the man was shot and other officers responded, he continued to resist arrest so police had to Taser him twice, Camden said.

The man was taken to Advocate Christ Medical Center in an unknown condition, Camden said.

The bus driver and a passenger were also hospitalized for non-life threatening injuries, according to Camden. The police officers were not injured, according to the News Affairs statement.

The suspect, who recently had gotten out of prison and is described as being extremely muscular, also had attacked a female passerby while out of the bus, according to police.

A Justice Department investigation will allege sweeping patterns of discrimination within the Ferguson, Mo., Police Department and at the municipal jail and court, a law enforcement official familiar with the report said Tuesday.